Hadn't even heard of this place prior to driving by the National Monument signs on the highway. My Honda Civic just barely survived the private logging roads you need to take to get back to the National Monument. While the roads are rough for a sedan, don't expect anything that would challenge an off road vehicle.
The beauty is all about the solitude and unspoiled beauty afforded by the site. This is the part that makes it hard for me to recommend because I really don't want people to flock to it as they have with so many other beautiful spots. Part of the joy was the fact we would go more than an hour without hearing anything other than the sounds of the woods. No motors, no planes... just nature.
Don't be mislead by the name, there is no specific monument to look at. The monument is the woods themselves. This isn't about scenic vistas or Sunday drives. It's all about enjoying unspoiled nature.
If you're looking for some place to park an RV, or for a casual escape during a road trip, then I recommend looking somewhere else. This is for people willing to leave modern conveniences behind to just enjoy the wind through the trees.